Spa shell



FIG. 1 is a perspective view of a spa shell showing our design;

FIG. 2 is a perspective view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a cross-sectional view taken along 4-4 of FIG. 3;

FIG. 5 is a cross-sectional view taken along 5-5 of FIG. 3;

FIG. 6 is a cross-sectional view taken along 6-6 of FIG. 3; and,

FIG. 7 is a cross-sectional view taken along 7-7 of FIG. 3.

The broken-line disclosure in the views represents portions of the article in which the claimed design is embodied, but which form no part of the claimed design. 

The ornamental design for a spa shell, as shown and described. 